Laser-assisted slow tool servo diamond turning of single-crystal silicon for fabricating micro-lens arrays

Single-crystal silicon is extensively applied in electronic devices, but the traditional ultraprecision diamond turning methods easily cause worse surface quality or surface microcracks when machining micro-lens arrays (MLAs). For this reason, this paper proposes the laser-assisted slow tool servo diamond turning (LA-STSDT) method to generate high-quality MLAs. Firstly, the working principle of the LA-STSDT method was introduced in detail. Then, machining experiments were performed to fabricate these MLAs. Experimental results showed the MLAs without any microcracks were successfully generated on the sample surface and its surface roughness Sa was less than 10 nm. Compared with the traditional fabrication method, it was improved by 45.3 %, demonstrating the effectiveness of the LA-STSDT method. Finally, a molecular dynamics model was established to explore the reason why the LA-STSDT method can improve surface quality. Therefore, this study offers a simple and effective method of fabricating high-quality MLAs on single-crystal silicon surfaces.